Tolong dengan caranya ya

No.17
3x + 2y = 5
2x - 5y = 16

eliminasi
15x + 10y = 25
4x - 10y = 32
--------------------- (+)
19x = 57
x = 57/19
x = 3

No. 18
3x - 2y = 5
x + 5y = -4
---------------- (+)
4x + 3y = 1      (D)

No.19
x = keramik tipe 1
y = keramik tipe 2 , maka
5x + 3y = 450
3x + 4y = 413

eliminasi
20x + 12y = 1800
9x + 12y = 1239
------------------------ (-)
11x = 561
x = 51

subtitusi
3x + 4y = 413
3(51) + 4y = 413
4y = 413 - 153
4y = 260
y = 65

jadi 2x + 5y
= 2(51) + 5(65)
= 102 + 325
= 427
jawaban = 427.000

No.20
x = anggur
y = apel
2x + 3y = 37.500
x + 2y = 21.000
----------------------- (-)
x + y = 16500
maka
Mela membeli 2 anggur dan 2 apel dengan 
2x + 2y = 33.000
Mela membayar dgn 50.000, kembaliannya adalah
50.000 - 33.000
= 17.000

No.21
3x + 2y = 2
2x + 5y = 16
eliminasi variabel x
6x + 4y = 4
6x + 15y = 48
------------------ (-)
11y = 44
y = 4

No. 22
4x + 3y - 7 = 0      →        4x + 3y = 7
4x - 1 - 3y = 0       →        4x - 3y = 1

eliminasi
4x + 3y = 7
4x - 3y = 1
---------------- (+)
8x = 8
x = 1

subtitusi
4x - 3y = 1
4(1) - 3y = 1
3y = 4 - 1
3y = 3
y = 1

HP = {(1,1)}

No.23
x = daging sapi
y = ayam potong,
Tina = 1 sapi + 2 ayam = 94.000
→ x + 2y = 94.000

Tini = 3 ayam + 2 sapi = 167.000
→ 2x + 3y = 167.000

jadi SPL adalah : opsi B